在绵羊模型中，部分凝血活酶时间和活化凝血时间用于肝素抗凝的体外比较。
An ex vivo comparison of partial thromboplastin time and activated clotting time for heparin anticoagulation in an ovine model.
机构信息
Department of Surgery, Division of Cardiac Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA.
出版信息
Artif Organs. 2022 Mar;46(3):501-505. doi: 10.1111/aor.14094. Epub 2021 Nov 2.
BACKGROUND
Sheep are a primary model of mechanical circulatory support (MCS) with heparin anticoagulation therapy frequently being monitored by activated clotting time (ACT) due to ease and cost. In patients undergoing long-term heparin therapy, other anticoagulation monitoring strategies, such as activated partial thromboplastin time (aPTT), have proven to be more reliable indicators for the adequacy of anticoagulation, frequently determined by heparin concentration. As there is a paucity of similar studies in sheep, we sought to investigate the correlation between heparin concentration and ACT and aPTT using whole sheep blood in an ex vivo model.
METHODS
Fresh whole blood was serially drawn from an adult female Dorset-hybrid sheep and aliquots were placed into tubes containing heparin saline solutions with concentrations ranging from 0 to 7.81 U heparin per mL of whole blood. ACT and aPTT values were measured on each of the samples. The experiment was performed four times with the same animal. A simple linear regression was performed to determine correlation, and subgroup analysis was performed on low versus high heparin concentrations typically seen in human patients on long-term MCS, such as extracorporeal membrane oxygenation (ECMO), versus cardiopulmonary bypass, respectively.
RESULTS
aPTT measurements versus the heparin concentration had an R = 0.7295. ACT measurements versus the heparin concentration had a R = 0.4628. aPTT measurements versus the ACT measurements had a R = 0.2974. The strength of the correlation between aPTT and heparin concentration increased at low heparin concentrations (R = 0.8392).
CONCLUSION
aPTT had a more reliable correlation to heparin concentration and thus anticoagulation level than ACT. This was particularly true at lower heparin concentrations, similar to ranges seen for patients on ECMO. The correlation between aPTT and ACT values was poor. Further in vivo studies should be performed to confirm our results.
背景
绵羊是机械循环支持（MCS）的主要模型，由于其简便性和成本效益，肝素抗凝治疗通常通过激活凝血时间（ACT）进行监测。在接受长期肝素治疗的患者中，其他抗凝监测策略，如活化部分凝血活酶时间（aPTT），已被证明是更可靠的抗凝充分性指标，通常通过肝素浓度来确定。由于在绵羊中此类研究较少，我们试图在体外模型中使用全绵羊血研究肝素浓度与 ACT 和 aPTT 之间的相关性。
方法
从一只成年雌性 Dorset 杂交绵羊中连续抽取新鲜全血，并将等分试样放入含有肝素生理盐水的管中，肝素生理盐水的浓度范围为每毫升全血 0 至 7.81 U 肝素。对每个样本测量 ACT 和 aPTT 值。该实验在同一只动物上进行了四次。进行简单线性回归以确定相关性，并对长期 MCS 患者（如体外膜氧合（ECMO））与体外循环分别处于低浓度和高浓度肝素的情况下的 aPTT 和 ACT 测量值进行亚组分析。
结果
aPTT 测量值与肝素浓度之间的 R ² 为 0.7295。ACT 测量值与肝素浓度之间的 R ² 为 0.4628。aPTT 测量值与 ACT 测量值之间的 R ² 为 0.2974。aPTT 与肝素浓度之间的相关性在低肝素浓度下增强（R ² 为 0.8392）。
结论
与 ACT 相比，aPTT 与肝素浓度和抗凝水平的相关性更可靠。在低肝素浓度下尤其如此，与 ECMO 患者的范围相似。aPTT 和 ACT 值之间的相关性较差。应进行进一步的体内研究来验证我们的结果。
Zotero 插件